The role of a nurse is extremely significant during the treatment process since she is constantly with the patient.The duty of the nurse is not only the treatment of illness but the perception of the human as an integral being. A nurse needs to be patient, human, tolerant, responsible and professional.Psychiatric patients often don´t want to accept their condition as an illness and are far more distrustful than patients with somatic disorders. Nowadays, bipolar affective disorder is one of the most common disorders. A medical treatment plan should be individual for every patient. Emotional state of a patient varies from manic to depressive and it is necessary to make a special plan of a medical treatment for manic and for a depressive episode. BAD is considered as the leading psychiatric disorder regarding the risk of a suicidal behaviour. A nurse has to build a relationship of confidence with the patient so that the patient can confide in her and express its feelings. The aim is to present specificities of the bipolar affective disorder, that is, its phases, to show how can they be recognised, treated and to show the role of the nurse within the work with a patient with bipolar affective disorder. In addition to that, here is a depiction of a suicide and a suicidal behaviour within the bipolar affective disorder and instructions how to recognise a suicidal behaviour, how to treat and prevent the suicide attempt or the suicide.